scons: Pass MAXLINELENGTH to scons invocation

scons: Pass MAXLINELENGTH to scons invocation

This helps in overcoming a problem when using scons with ccache enabled.
When commands get longer, then it resorts to using response files to do
the operations e.g. @/tmp/tmp96j6icra.lnk when this response file is
inboked by compiler it works ok, however, this does not when ccache is
used to invoke the complilation. We see errors e.g.

ccache @/tmp/tmppsyij_0v.lnk
ccache: error: execute_noreturn of @/tmp/tmppsyij_0v.lnk failed: No such file or directory

Using MAXLINELENGTH setting ensures that we can use ARG_MAX to extend
the length of commandline and hence avoid using response files. This
issue is also reported in mongodb [1]

[1] https://jira.mongodb.org/browse/SERVER-38389

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>